Found this on another discussion board...unfortunately there was no source mentioned but it seems legit. It was in another article about the AA 767 winglets.

Quote:Meanwhile, United is expected to become the latest major 757 operator to announce selection of the blended winglet to reduce fuel costs. The airline, which currently operates 97 757-200s, is expected to start by retrofitting aircraft from September onwards. Other 757 winglet customers include American Airlines, Continental Airlines and Northwest Airlines, while LaMoria adds that others including Delta Airlines are “very interested.”

Quoting Laxintl (Reply 1):Indeed. Actually its not a mystery except the company has decided to sit on the news for quite some time. The Hawaii etops B757s along with p.s. aircraft are due for retrofitting commencing September.

So I take it only the ETOPS (incl. p.s.) 757s will be receiving winglets, or do they plan to eventually mod the entire fleet?